A new type capacitive MEMS accelerometer digital interface circuit design

被引：0

作者：

Li, Zong-Wei ^{[1
,2
]}

Cong, Ning ^{[1
,2
]}

Xiong, Xing-Yin ^{[1
,2
]}

Han, Ke-Du ^{[1
]}

Yang, Chang-Chun ^{[1
]}

机构：

[1] Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing,100029, China

[2] University of Chinese Academy of Sciences, Beijing,100049, China

来源：

Tien Tzu Hsueh Pao/Acta Electronica Sinica | 2016年 / 44卷 / 10期

关键词：

Analog to digital conversion - Integrated circuit design - Digital arithmetic - Integrated circuit manufacture - System stability - Accelerometers - Floors;

D O I：

10.3969/j.issn.0372-2112.2016.10.032

中图分类号：

学科分类号：

摘要：

The circuit offset often causes integration saturation in the traditional sigma-delta interface of capacitive MEMS accelerometers.To address this problem,a new type of capacitive digital interface circuit used for downhole exploration and oil detection is designed.This paper presents a MEMS-based 5th-order sigma-delta capacitive accelerometer,where the 3rd-order digital loop filter is realized using FPGA.This will reduce the ASIC analog circuit layout design and chip testing difficulties and is easy to optimize the loop filter parameters,which can be used to improve the system stability and optimize the noise performance.The analog-frond-end amplifier (AFE) is realized by using a simple correlated double sampling (CDS),which is one effective method to reduce circuit offset of AFE.According to the Gaussian distribution of AFE output signal,one new type 8-bit instantaneous floating point ADC (IFP ADC) is designed.The IFP ADC is used to convert analog signal of AFE to digital signal to feed the 3rd-order digital loop filter.The whole system provides a significantly low noise floor 53.09ng/rt(Hz) overall a 200 Hz bandwidth.In this work,the AFE amplifier and ADC were successfully fabricated by using XFAB XH018 mixed-signal CMOS process.Furthermore,the sensitivity and noise floor of the AFE amplifier are 0.69V/pF and 3.20μV/rt(Hz) in open loop measurement,respectively. © 2016, Chinese Institute of Electronics. All right reserved.

引用

页码：2507 / 2513